The present invention is related to a method of fabricating a fire detector, and more particularly to a method of fabricating various types of fire detectors by selecting a combination of common units, and to fire detectors thus fabricated.
There have been proposed a wide variety of fire detectors designed for specific purposes or situations. In terms of a fire sensing elements, the fire detectors can be classified generally into three types of using a smoke sensor, a thermal sensor, and a combination thereof. Also, the fire detectors can have different schemes of determining an outbreak of fire or fire-presence, for example, by analyzing a sensed parameter of the smoke density and/or temperature in accordance with a sophisticated program, or simply by comparing the parameter with a reference value. Further, the fire-presence signal may be simply a short-circuit signal on a transmission line to a receiver, or may carry address assigned to each detector for precisely locating the presence of fire at the receiver. Therefore, depending on specific particular needs in consideration of a scale of fire detection system, an environment, cost and other factors, the detector is selected from a large number of combinations of the sensing elements, the fire-presence determination schemes, and the transmission of the fire-presence signal. The detectors of different specifications have been fabricated individually as different models in conformity with various needs. However, the different models are normally designed to have exclusive parts some of which are not shared with other models. This becomes critical when most of the parts of the detector are integrated into a single chip. Therefore, a manufacture has to prepare and stock a large kinds of exclusive parts for production of various types of the detector, which leads to a cost increase of the fire detector.
In view of the above problem, the present invention has been accomplished to provide a method which enables to fabricate various models of fire detectors only from a limited number of common parts or units. Therefore, it is a primary object of the present invention to provide a method which is capable of producing various models of fire detectors in accordance with user""s specific needs at a reduced cost. The method in accordance with the present invention utilizes a smoke sensor unit 1, a thermal sensor unit 2, a signal processing unit 3, a signal transmission unit 4, and a power unit 5, and then combines at least one of the smoke sensor unit and the thermal sensor unit with the power unit and optionally with at least one of the signal processing unit and the signal transmission unit.
The smoke sensor unit is provided to sense a smoke density and generate a smoke density signal indicative thereof, in addition to generating a fire-determination signal indicative of the fire-presence or not as determined based upon the sensed smoke density. The smoke sensor unit includes a power input terminal T11 for receiving an operating voltage, a smoke density output terminal T13 for providing the smoke density signal, and a fire-determination output terminal T14 for providing the fire-determination signal.
The thermal sensor unit 2 is provided to sense an environmental temperature and generate a temperature signal indicative thereof. The thermal sensor unit includes a power input terminal T21 for receiving the operating voltage, and a temperature output terminal T22 for providing the temperature signal.
The signal processing unit 3 is provided to determine the fire-presence based upon any of the smoke density signal and said temperature signal, and to generate a fire-determination signal. The signal processing unit has a smoke density input terminal T33 for receiving the smoke density signal, a temperature input terminal T32 for receiving the temperature signal, a fire-determination output terminal T34 for providing the fire-determination signal, an interrogation signal input terminal T35 for receiving an interrogation signal, and a power input terminal T31 for receiving the operating voltage.
The signal transmission unit 4 is responsible for signal transmission with a receiver 6 and is configured to convert the fire-determination signal into a multiplex signal for multiplex transmission to the receiver, and to transform the interrogation signal from the receiver into a suitable format to be processed at the signal processing unit 3. The signal transmission unit has a power input terminal T41 for receiving the operating voltage, an interrogation input terminal T45 for receiving the interrogation signal, a fire-determination input terminal T42 for the fire-determination signal, an interrogation signal output terminal T43 for transmitting the interrogation signal, and an multiplex signal output terminal T46 for transmitting the multiplex signal to the receiver through the power unit.
The power unit 5 is provided to give the operating voltage and includes a switch circuit 18 which is connected to the receiver for providing a short-circuit signal when the fire-determination signal indicates the fire-presence. Also included in the power unit is a transfer circuit 52 which transfers the interrogation signal from the receiver to the signal transmission unit as well as the multiplex signal from the signal transmission unit to the receiver. The power unit has a power output terminal T51 for providing the operating voltage, a multiplex signal input terminal T56 for receiving the multiplex signal, an interrogation output terminal T55 for providing the interrogation signal, a fire-determination input terminal T54 for receiving the fire-determination signal, and a port T52, T53 for connection with the receiver.
Since each unit is configured to have the input and output terminals for immediate connection with those of a corresponding unit or units, the detector in any desired combination of the units can be readily assembled.
In a preferred embodiment, at least one of the smoke sensor unit, the thermal sensor unit, the signal processing unit, the signal transmission unit, the power unit is prepared In the form of an integrated circuit for facilitating the assembly of the detector, in addition to making the detector compact.
One example of the fire detector fabricated in accordance with the present invention is equipped with all the units 1 to 5, in which the smoke sensor unit 1 has the smoke density output terminal T13 connected to the smoke density input terminal T33 of the signal processing unit 3, the thermal sensor unit 2 has the temperature output terminal T22 connected to the temperature input terminal T32 of the signal processing unit 3, the signal processing unit 3 has the fire-determination output terminal T34 connected to the fire-determination input terminal T42 of the signal transmission unit 4, the signal processing unit 3 has the interrogation input terminal T35 connected to the interrogation output terminal T43 of the signal transmission unit 4, the signal transmission unit 4 has the multiplex signal output terminal T46 connected to the multiplex signal input terminal T56 of the power unit 5, the signal transmission unit 4 having the interrogation input terminal T45 connected to the interrogation output terminal T55 of the power unit 5, and the power unit 5 has the power output terminal T51 connected to the power input terminals T11, T21, T31, and T41 of the smoke sensor unit, the thermal sensor unit, the signal processing unit, the signal transmission unit.
These and still other objects and advantageous features of the present invention will become more apparent from the following description of the embodiment when taken in conjunction with the attached drawings.